Anthropology: Human Evolution

anthropology

the study of humans

biological anthropology

focuses on biological and behavioral aspects of human

central question in the course

what does it mean to be human?

humans on the tree of life

animals, mammals, primates, apes, homo sapiens

bipedalism

walks/is mobile on two feet/legs

facultative bipedalism

occasionally bipedal in specific/necessary situations

sexual dimorphism

differences in appearance, size, or behaviors between males and females of the same species, driven by evolution

precocial

born mature and mobile, capable shortly after birth

altricial

underdeveloped, requires parental care longer after birth

material culture

culture constantly interacting with physical objects, tools, phones, etc

8 uniquely human traits

obligate bipedalism, complex language, reduced dimorphism, small teeth/small canines, slow pace of development and growth, fully opposable thumbs, object interaction, increased sweat glands

phenotype

an organism’s observable physical traits

evolution

change in heritable characteristics of biological populations over successive generations

natural selection

the process through which species adapt to their environments and evolve over time

Darwin and Wallace “descent with modification”

describes how species change over generations, encompasses three main ideas: inheritance of traits, natural selection, and gradual change

How did Darwin's idea of evolution

differ from Lamarck’s?

Darwin emphasizes natural selection and the inheritance of preexisting traits, while Lamarck focuses on the inheritance of acquired characteristics through use and disuse

necessary conditions for natural selection to occur

variation of a trait, inheritance of a trait, differential reproductive success

evolutionary fitness

an organism’s ability to survive and reproduce in its environment

stabilizing selection:

average traits have more reproductive success

directional selection

one extreme of a trait has more reproductive success

disruptive selection

both extremes of a trait have more reproductive success

modes of natural selection

stabilizing selection, directional selection, disruptive selection